Held in conjunction with the Monaco Historic Grand Prix, the RM Sotheby’s Monaco sale takes place on May 14. The run list features dozens of mouth-watering classic sports and racing cars as well as almost 40 lots from the Quattroruote Collection. Most of the Quattroruote cars are prewar machines, and the highlight is a Gangloff-bodied Bugatti Type 57.

As usual, the rest of the Monaco sale is packed with top-shelf collector cars and only seven of the vehicles offered have a presale estimate under six figures. With so much history and so much money crossing the block in Monaco it’s hard to choose favorites, but here are five cars that we’ll be watching.

Porsche won its 16th overall victory at Le Mans with the 911 GT1. Unlike competition cars such as the McLaren F1, the Porsche was a racing machine from the start that differed from the normal 911 in numerous ways, including the fact that its flat-six was water-cooled instead of air-cooled and mid-mounted instead of rear-mounted. Porsche made a total of 41 911 GT1s, including 23 street cars. The example on offer in Monaco was delivered as a bare tub to a private team in North America that had wrecked their other GT1. Parts from that car were combined with Evolution upgrades to complete the car seen here, which won the Canadian GT Championship from 1999-2001. It was restored last year and is currently road registered. According to RM Sotheby’s, it is the only road-legal 911 GT1 racecar. While the presale estimate is serious money, it still looks like a bargain compared to a similar (and more common) McLaren F1.

In 1951, Ferrari was still relatively young as a full-blown car manufacturer. But it was already a powerful force in international sports car racing having won the first postwar 24 Hours of Le Mans in 1949 and numerous other high profile events. Ferrari built 23 examples of the 340 America, and the one offered by RM Sotheby’s ran at Le Mans in 1951 and 1952. Luigi Chinetti ran it for owner Pierre Louis-Dreyfus, a French businessman who also shared driving duties with Louis Chiron in 1951 and René Dreyfus in 1952. It didn’t win glory at Le Mans and had no other significant race results, but it remains a fully documented, matching numbers example and was recently restored to its 1951 Le Mans specs. Early racing Ferraris are extremely collectible, and this car is the real deal.

The Group B Rally Era of 1982-86 was probably the World Rally Championship’s most exhilarating era thanks to the flame-spitting, 600-hp monsters from Audi, Peugeot, Lancia and Ford. At auction, there has been recent interest in the related street legal homologation specials as several examples of cars like the Audi Sport Quattro and Ford RS200 have brought big money. Few examples of the actual Group B rally cars themselves, however, have come to market. The Peugeot 205 offered in Monaco is a works car that was driven by 1981 World Champion Ari Vatanen to victory at both the Rallye Monte-Carlo and the Swedish Rally in 1985, the year that Peugeot won its first World Rally Championship. The all-wheel drive 205 Rally car was turbocharged to make 345-hp from just 1.8-liters

There were just 10 NART Spiders built, and the one offered by RM Sotheby’s is the last of them as well as the only one sold new in Europe. The car has an interesting, fully documented history going back to its first owner in Spain, and the NART Spider is the crème-de-la-crème of road-going Ferraris. This car does not have the same kind of provenance as some of the other NART Spiders, so RM’s somewhat conservative estimate seems appropriate. Even so, the other nine cars are apparently in long-term collections, so this might be the only example we see come to market for quite some time.

The TZ is no ordinary Alfa Giulia. The TZ stands for Tubolare Zagato, which refers to its tube frame and aluminum Zagato bodywork, and other performance tweaks included a taller fifth gear, limited-slip differential and inboard rear disc brakes. In race tune, the 1,600-cc twin cam could make 170-hp, and the aerodynamic body allowed for speeds well over 130 mph. The TZ offered by RM Sotheby’s is the 39th of 101 built, and was raced in period throughout Italy. It was restored in the 1980s and has been vintage raced since, so it’s likely more at home on a track than a show field.